In a bowl, mix oats and buttermilk; let stand at least 15 minutes or up to 30 minutes.

Meanwhile, in a small bowl, mix flour, sugar, baking soda, baking powder, and salt.

In a large bowl, beat eggs, milk, and vanilla to blend. Stir in flour and oat mixtures just until evenly moistened.

Place a nonstick frying pan over medium heat, when hot, coat lightly with oil and adjust heat to maintain temperature. Pour batter in 1/2-cup portions onto pan and cook until pancakes are browned on the bottom and edges begin to look dry, about 2 minutes.

Flip the pancakes with a wide spatula and brown other side, for about 1 1/2 to 2 minutes longer. Coat pan with more oil as necessary to cook remaining pancakes.

Serve the pancakes as warm with butter and syrup.